The aim of these studies was to evaluate the b iomechanical characteristics of two devices and provide information for clinical choice. In vitro cadaveric spine testing which consisted of the stability test and the yield strength test was performed. In hemicorpectomy model, the AF was s tiffer than the Kaneda in flexion, extension and left lateral bending (P<0.0 1). In total corpectomy model, the AF was stiffer than the Kaneda in flexion,lef t lateral bending and axial rotation (P<0.01). The average values of yield s trength(M) for the Kaneda,the AF and the intact were 477.3 kg,544.4 kg and 493.6 kg resectively. The stability of the AF is superior to that of the Kaneda. In t otal corpectomy, the Kaneda is significantly unstable in axial rotation. Both de vices restore effectively load carrying capacity of the spine.